function ShowVennDiagram ( l, i, r, mousemove_event ) {
  posx=mousemove_event.getClientX();
  posy=mousemove_event.getClientY();

  var vdg = svgdoc.getElementById ( "vdg" );
  vdg.setAttribute ( "transform", "translate(" + (posx - 45) + " " + posy + ") scale(2)" );
  vdg.setAttribute ( "display", "inline" );

  svgdoc.getElementById ( "vd_lc" ).firstChild.data = l;
  svgdoc.getElementById ( "vd_rc" ).firstChild.data = r;
  svgdoc.getElementById ( "vd_int" ).firstChild.data = i;
}

function HideVennDiagram ( evt ) {
  var vdg = svgdoc.getElementById ( "vdg" );
  if ( !vdg ) return;

  vdg.setAttribute ( "display", "none" );
}
